Christian rudolph



UNITED STATES PATENT FFTCE.

CHRISTIAN RUDOLPH, OF OFFENBAOH-ON-THE-MAIN, GERMANY, ASSIGNOR TO THE FIRM OF K. OEHLER, OF SAME PLACE.

RED-BLUE DIAZO DYE.

SPECIFICATION forming part of Letters Patent No. 579,773, dated March 30, 1897. Application filed December 2, 1893. Serial No. 492,599. (Specimens) Patented in England November 2O 1893, No. 22,204.

To all whom it may concern.-

Be it known that I, CHRISTIAN RUDOLPH, chemist, a subject of the Emperor of Germany, and a resident of OfEenbach-on-the- Main, in the Empire of Germany, have invented new and useful Improvements in the Method of Producing Azo Dyestuffs from Alpha Alpha Amido-Oxynaphthalene Beta Beta Disulfo-Acid, (and for which I have obtained Letters Patent of Great Britain, No. 22,204., dated November 20, 1893,) of which the following is a specification.

The intermediate compound obtained in an alkaline solution from one molecule of a paradiamin and one molecule of alpha alpha, amidooxynaphthalene beta beta disulfo-acid yields new and Valuable azo dyestuffs when further combined with one molecule of an aromatic amin or phenole. From the whole series of these dyestuffs, which dye cotton without mordant, I have especially produced the following two:

Tolidin Azoa1pha,alpha,amidooxynaphthalene beta beta disulfo-acid on NH,

The dyestuffs form a dark blackish-brown. powder with a feeble metallic luster. They are soluble in water with a violet and in concentrated sulfuric acid with a blue color. They dye unmordanted cotton pure red-blue.

Azo 2, 3 clioxynaphthalene.

pha,alpl1a amidooxynaphthalene beta betadisulfo-acid. After a short time a dissolution of eight parts of 2.3 dioxynaphthalene and of four parts of caustic soda in one hundred parts of water is added. The mixture is allowed to stand for twenty-four hours and is then heated. The dyestu ff is precipitated by common salt, filtered off, pressed, and dried.

The formula in accordance with which the herein-described dyestufi is produced may be expressed as follows:

OH NH,

some

What I claim, and desire to secure by Letters Patent, is

l. The method of producing red-blue di azo dyestuffs by the combination of tetrazo-ditolyl-ortetrazo-diphenyl with one molecule metallic luster, soluble in water with a violet and in concentrated sulfuric acid with a blue color and which dyes unmordanted cotton r 5 pure red-blue.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

CHRISTIAN RUDOLPH.

Witnesses JEAN GRUND, FRANK H. MASON. 

